Sökning: "magnetic noise"

Visar resultat 6 - 10 av 123 avhandlingar innehållade orden magnetic noise.

  1. 6. Radio Frequency Systems for NMR Imaging: Coil Development and Studies of Non-Thermal Biological Effects

    Författare :Lars Malmgren; Lunds universitet; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; anechoic chamber; TEM transmission cells; FDTD; circularly polarized electromagnetic fields; reduced coupling; noise matching; matching networks; low noise amplifiers; upper thoracic spine; surface coils; Nuclear magnetic resonance; magnetic resonance imaging; non-thermal biological effects; blood-brain barrier; Electronics; Elektronik;

    Sammanfattning : This thesis concerns both design and optimization of NMR imaging systems and studies on non-thermal biological effects of electromagnetic fields. These two research fields are linked together by the fact that humans are subject to static and pulsed magnetic fields as well as to magnetic radio frequency fields (RF) during an NMR imaging investigation. LÄS MER

  3. 7. On modelling of magnetic noise in inductionmotors

    Författare :Kelvin C. Maliti; KTH; []
    Nyckelord :;

    Sammanfattning : .... LÄS MER

  4. 8. Improved performance characteristics of induction machines with non-skewed symmetrical rotor slots

    Författare :Rathna Chitroju; Chandur Sadarangani; Kelvin C Maliti; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; skewing; cross current losses; radial magnetic forces; magnetic noise; asymmetrical rotor slots; eccentricity; stator vibration; two-dimensional fast fourier transform; finite element method; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

    Sammanfattning : Induction machines convert more than 55% of electrical energy into various other forms in industrial and domestic environments. Improved performance, especially by reduction of losses in induction machines hence can significantly reduce consumption of electricity. LÄS MER

  5. 9. Cryogenic InP High Electron Mobility Transistors in a Magnetic Field

    Författare :Isabel Harrysson Rodrigues; Chalmers tekniska högskola; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; magnetic field; cryogenic; low noise amplifier; angular dependence; InP HEMT; geometrical magnetoresistance;

    Sammanfattning : The InGaAs-InAlAs-InP high electron mobility transistor (InP HEMT) is the preferred active device used in a cryogenic low noise amplifier (LNA) for sensitive detection of microwave signals. In this thesis it is demonstrated that the InP HEMT, when placed in a magnetic field, has a strong angular dependence in its output current. LÄS MER

  7. 10. Design, Modelling and Control of Electrical Machines - With Applications to Iron-powder Machines and Acoustic Noise

    Författare :David Martinez; Industriell elektroteknik och automation; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; BEM; induction machine; noise prediction; vector control; acoustic noise; HEV; series magnetization; leakage reduction; thermal model; FEM; MEC; claw-poles; SMC; slip-ring-less machine; sound intensity measurements; vibration; Electrical engineering; Elektroteknik;

    Sammanfattning : This thesis consists of two parts, the first dealing with the design of iron-powder synchronous machines, and the second with the analysis and prediction of the acoustic noise in electrical machines. In Part I, a 1.6 kW electrically magnetized claw-pole machine with magnetically conducting end-plates has been analyzed and a prototype tested. LÄS MER